The theory of electrical stimulation therapy for pain control has been studied at significant length since it was initially theorized. Historically, the use of electrical properties to control pain dates back to 46 AD when torpedo fish were used to treat headache and gout. The theory behind the effectiveness of the use of electrical stimulation for pain has been described as the gate theory of pain modulation, which describes how pain stimulation can be blocked from reaching the brain by other signals. This theory has provided the bases for pain management with electrical stimulation using different modalities. In the 1950s, the use of interferential current therapy (IFC) was developed to provide dual current therapy to provide deeper tissue penetration to allow for improved pain relief.
In the field of orthopedic surgery, several studies have compared the use of electrical stimulation therapy for patient pain relief with differing results. Two systematic reviews were done comparing use of transcutaneous electrical nerve stimulation (TENS) as a possible adjunct after total knee arthroplasty (TKA). Both studies found significant improvement of pain scales and active knee range of motion.
More specifically, IFC therapy has also been compared to both TENS and placebo for pain relief. When compared to TENS for back pain, there are conflicting results. Some studies indicate overall pain improvement but no difference between modalities. Another study found IFC to be more effective in treating chronic low back pain due to deeper tissue penetration. The author of this patent application is an Orthopedic Surgeon, and has compared TENS unit treatment to IFC treatment in clinical practice with findings of IFC use to be far more effective than TENS for treatment of muscular and neurogenic pain.
One study out of Kerlan-Jobe Orthopaedic clinic in 2001 compared IFC therapy to placebo for post-operative pain, edema and range of motion after ACL, meniscectomy or knee chondroplasty. In this randomized, double-blind, placebo controlled prospective study, patients were treated post-operative with IFC therapy providing therapeutic or placebo electrical stimulation. In the study, all IFC subjects reported significantly less pain and greater range of motion for all reviewed time points.
The present invention improves upon the Kerlan-Jobe study by providing for a system and method employing IFC therapy that may be used by patients following orthopedic surgeries, for example, following knee arthroplasty surgery. The present invention provides for improved patient outcomes, which result in shorter hospital stay, reduced use of opioid medication and decreased need for manipulation under anesthesia.